diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 479 |
1 files changed, 284 insertions, 195 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 224dc3c23..9012aa704 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -32,14 +32,20 @@ #![feature(box_patterns)] #![feature(let_chains)] -#![feature(let_else)] +#![cfg_attr(bootstrap, feature(let_else))] #![feature(never_type)] #![recursion_limit = "256"] #![allow(rustc::potential_query_instability)] +#![deny(rustc::untranslatable_diagnostic)] +#![deny(rustc::diagnostic_outside_of_impl)] #[macro_use] extern crate tracing; +use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait, TraitFnAsync}; + +use rustc_arena::declare_arena; +use rustc_ast::ptr::P; use rustc_ast::visit; use rustc_ast::{self as ast, *}; use rustc_ast_pretty::pprust; @@ -49,7 +55,7 @@ use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::sorted_map::SortedMap; use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; use rustc_data_structures::sync::Lrc; -use rustc_errors::{struct_span_err, Applicability, Handler}; +use rustc_errors::{DiagnosticArgFromDisplay, Handler, StashKey}; use rustc_hir as hir; use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res}; use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID}; @@ -75,6 +81,7 @@ macro_rules! arena_vec { mod asm; mod block; +mod errors; mod expr; mod index; mod item; @@ -89,6 +96,13 @@ struct LoweringContext<'a, 'hir> { /// Used to allocate HIR nodes. arena: &'hir hir::Arena<'hir>, + /// Used to allocate temporary AST nodes for use during lowering. + /// This allows us to create "fake" AST -- these nodes can sometimes + /// be allocated on the stack, but other times we need them to live longer + /// than the current stack frame, so they can be collected into vectors + /// and things like that. + ast_arena: &'a Arena<'static>, + /// Bodies inside the owner being lowered. bodies: Vec<(hir::ItemLocalId, &'hir hir::Body<'hir>)>, /// Attributes inside the owner being lowered. @@ -126,8 +140,23 @@ struct LoweringContext<'a, 'hir> { allow_try_trait: Option<Lrc<[Symbol]>>, allow_gen_future: Option<Lrc<[Symbol]>>, allow_into_future: Option<Lrc<[Symbol]>>, + + /// Mapping from generics `def_id`s to TAIT generics `def_id`s. + /// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic + /// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this + /// field from the original parameter 'a to the new parameter 'a1. + generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>, } +declare_arena!([ + [] tys: rustc_ast::Ty, + [] aba: rustc_ast::AngleBracketedArgs, + [] ptr: rustc_ast::PolyTraitRef, + // This _marker field is needed because `declare_arena` creates `Arena<'tcx>` and we need to + // use `'tcx`. If we don't have this we get a compile error. + [] _marker: std::marker::PhantomData<&'tcx ()>, +]); + trait ResolverAstLoweringExt { fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>>; fn get_partial_res(&self, id: NodeId) -> Option<PartialRes>; @@ -136,12 +165,6 @@ trait ResolverAstLoweringExt { fn get_lifetime_res(&self, id: NodeId) -> Option<LifetimeRes>; fn take_extra_lifetime_params(&mut self, id: NodeId) -> Vec<(Ident, NodeId, LifetimeRes)>; fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind; - /// Record the map from `from` local def id to `to` local def id, on `generics_def_id_map` - /// field. - fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId); - /// Get the previously recorded `to` local def id given the `from` local def id, obtained using - /// `generics_def_id_map` field. - fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId; } impl ResolverAstLoweringExt for ResolverAstLowering { @@ -209,41 +232,6 @@ impl ResolverAstLoweringExt for ResolverAstLowering { fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind { self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang) } - - /// Push a remapping into the top-most map. - /// Panics if no map has been pushed. - /// Remapping is used when creating lowering `-> impl Trait` return - /// types to create the resulting opaque type. - #[tracing::instrument(level = "debug", skip(self))] - fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId) { - self.generics_def_id_map.last_mut().expect("no map pushed").insert(from, to); - } - - fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId { - // `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we - // push new mappings so we need to try first the latest mappings, hence `iter().rev()`. - // - // Consider: - // - // `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}` - // - // We would end with a generics_def_id_map like: - // - // `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]` - // - // for the opaque type generated on `impl Sized + 'b`, We want the result to be: - // impl_sized#'b, so iterating forward is the wrong thing to do. - for map in self.generics_def_id_map.iter().rev() { - if let Some(r) = map.get(&local_def_id) { - debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`"); - local_def_id = *r; - } else { - debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map"); - } - } - - local_def_id - } } /// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree, @@ -264,6 +252,7 @@ enum ImplTraitContext { ReturnPositionOpaqueTy { /// Origin: Either OpaqueTyOrigin::FnReturn or OpaqueTyOrigin::AsyncFn, origin: hir::OpaqueTyOrigin, + in_trait: bool, }, /// Impl trait in type aliases. TypeAliasesOpaqueTy, @@ -323,7 +312,7 @@ impl std::fmt::Display for ImplTraitPosition { } } -#[derive(Debug)] +#[derive(Debug, PartialEq, Eq)] enum FnDeclKind { Fn, Inherent, @@ -335,9 +324,17 @@ enum FnDeclKind { } impl FnDeclKind { - fn impl_trait_return_allowed(&self) -> bool { + fn impl_trait_return_allowed(&self, tcx: TyCtxt<'_>) -> bool { match self { FnDeclKind::Fn | FnDeclKind::Inherent => true, + FnDeclKind::Impl if tcx.features().return_position_impl_trait_in_trait => true, + _ => false, + } + } + + fn impl_trait_in_trait_allowed(&self, tcx: TyCtxt<'_>) -> bool { + match self { + FnDeclKind::Trait if tcx.features().return_position_impl_trait_in_trait => true, _ => false, } } @@ -430,10 +427,13 @@ pub fn lower_to_hir<'hir>(tcx: TyCtxt<'hir>, (): ()) -> hir::Crate<'hir> { tcx.definitions_untracked().def_index_count(), ); + let ast_arena = Arena::default(); + for def_id in ast_index.indices() { item::ItemLowerer { tcx, resolver: &mut resolver, + ast_arena: &ast_arena, ast_index: &ast_index, owners: &mut owners, } @@ -500,6 +500,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } /// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name + /// resolver (if any). + fn orig_opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> { + self.resolver.node_id_to_def_id.get(&node).map(|local_def_id| *local_def_id) + } + + fn orig_local_def_id(&self, node: NodeId) -> LocalDefId { + self.orig_opt_local_def_id(node) + .unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node)) + } + + /// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name /// resolver (if any), after applying any remapping from `get_remapped_def_id`. /// /// For example, in a function like `fn foo<'a>(x: &'a u32)`, @@ -513,16 +524,36 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { /// we would create an opaque type `type FooReturn<'a1> = impl Debug + 'a1`. /// When lowering the `Debug + 'a` bounds, we add a remapping to map `'a` to `'a1`. fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> { - self.resolver - .node_id_to_def_id - .get(&node) - .map(|local_def_id| self.resolver.get_remapped_def_id(*local_def_id)) + self.orig_opt_local_def_id(node).map(|local_def_id| self.get_remapped_def_id(local_def_id)) } fn local_def_id(&self, node: NodeId) -> LocalDefId { self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node)) } + /// Get the previously recorded `to` local def id given the `from` local def id, obtained using + /// `generics_def_id_map` field. + fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId { + // `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we + // push new mappings, so we first need to get the latest (innermost) mappings, hence `iter().rev()`. + // + // Consider: + // + // `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}` + // + // We would end with a generics_def_id_map like: + // + // `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]` + // + // for the opaque type generated on `impl Sized + 'b`, we want the result to be: impl_sized#'b. + // So, if we were trying to find first from the start (outermost) would give the wrong result, impl_trait#'b. + self.generics_def_id_map + .iter() + .rev() + .find_map(|map| map.get(&local_def_id).map(|local_def_id| *local_def_id)) + .unwrap_or(local_def_id) + } + /// Freshen the `LoweringContext` and ready it to lower a nested item. /// The lowered item is registered into `self.children`. /// @@ -591,9 +622,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { remap: FxHashMap<LocalDefId, LocalDefId>, f: impl FnOnce(&mut Self) -> R, ) -> R { - self.resolver.generics_def_id_map.push(remap); + self.generics_def_id_map.push(remap); let res = f(self); - self.resolver.generics_def_id_map.pop(); + self.generics_def_id_map.pop(); res } @@ -644,14 +675,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { ) -> (Fingerprint, Fingerprint) { self.tcx.with_stable_hashing_context(|mut hcx| { let mut stable_hasher = StableHasher::new(); - hcx.with_hir_bodies(true, node.def_id(), bodies, |hcx| { + hcx.with_hir_bodies(node.def_id(), bodies, |hcx| { node.hash_stable(hcx, &mut stable_hasher) }); let hash_including_bodies = stable_hasher.finish(); let mut stable_hasher = StableHasher::new(); - hcx.with_hir_bodies(false, node.def_id(), bodies, |hcx| { - node.hash_stable(hcx, &mut stable_hasher) - }); + hcx.without_hir_bodies(|hcx| node.hash_stable(hcx, &mut stable_hasher)); let hash_without_bodies = stable_hasher.finish(); (hash_including_bodies, hash_without_bodies) }) @@ -663,6 +692,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { /// actually used in the HIR, as that would trigger an assertion in the /// `HirIdValidator` later on, which makes sure that all `NodeId`s got mapped /// properly. Calling the method twice with the same `NodeId` is fine though. + #[instrument(level = "debug", skip(self), ret)] fn lower_node_id(&mut self, ast_node_id: NodeId) -> hir::HirId { assert_ne!(ast_node_id, DUMMY_NODE_ID); @@ -696,6 +726,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } /// Generate a new `HirId` without a backing `NodeId`. + #[instrument(level = "debug", skip(self), ret)] fn next_id(&mut self) -> hir::HirId { let owner = self.current_hir_id_owner; let local_id = self.item_local_id_counter; @@ -767,7 +798,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } /// Converts a lifetime into a new generic parameter. - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn lifetime_res_to_generic_param( &mut self, ident: Ident, @@ -811,7 +842,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { /// name resolver owing to lifetime elision; this also populates the resolver's node-id->def-id /// map, so that later calls to `opt_node_id_to_def_id` that refer to these extra lifetime /// parameters will be successful. - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] #[inline] fn lower_lifetime_binder( &mut self, @@ -874,14 +905,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // the `HirId`s. We don't actually need HIR version of attributes anyway. // Tokens are also not needed after macro expansion and parsing. let kind = match attr.kind { - AttrKind::Normal(ref item, _) => AttrKind::Normal( - AttrItem { - path: item.path.clone(), - args: self.lower_mac_args(&item.args), + AttrKind::Normal(ref normal) => AttrKind::Normal(P(NormalAttr { + item: AttrItem { + path: normal.item.path.clone(), + args: self.lower_mac_args(&normal.item.args), tokens: None, }, - None, - ), + tokens: None, + })), AttrKind::DocComment(comment_kind, data) => AttrKind::DocComment(comment_kind, data), }; @@ -929,8 +960,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { lit.clone() } else { Lit { - token: token::Lit::new(token::LitKind::Err, kw::Empty, None), - kind: LitKind::Err(kw::Empty), + token_lit: token::Lit::new(token::LitKind::Err, kw::Empty, None), + kind: LitKind::Err, span: DUMMY_SP, } }; @@ -956,7 +987,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_assoc_ty_constraint( &mut self, constraint: &AssocConstraint, - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::TypeBinding<'hir> { debug!("lower_assoc_ty_constraint(constraint={:?}, itctx={:?})", constraint, itctx); // lower generic arguments of identifier in constraint @@ -967,18 +998,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } GenericArgs::Parenthesized(ref data) => { self.emit_bad_parenthesized_trait_in_assoc_ty(data); - self.lower_angle_bracketed_parameter_data( - &data.as_angle_bracketed_args(), - ParamMode::Explicit, - itctx, - ) - .0 + let aba = self.ast_arena.aba.alloc(data.as_angle_bracketed_args()); + self.lower_angle_bracketed_parameter_data(aba, ParamMode::Explicit, itctx).0 } }; gen_args_ctor.into_generic_args(self) } else { self.arena.alloc(hir::GenericArgs::none()) }; + let itctx_tait = &ImplTraitContext::TypeAliasesOpaqueTy; let kind = match constraint.kind { AssocConstraintKind::Equality { ref term } => { @@ -1016,9 +1044,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // then to an opaque type). // // FIXME: this is only needed until `impl Trait` is allowed in type aliases. - ImplTraitContext::Disallowed(_) if self.is_in_dyn_type => { - (true, ImplTraitContext::TypeAliasesOpaqueTy) - } + ImplTraitContext::Disallowed(_) if self.is_in_dyn_type => (true, itctx_tait), // We are in the parameter position, but not within a dyn type: // @@ -1040,15 +1066,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { self.with_dyn_type_scope(false, |this| { let node_id = this.next_node_id(); - let ty = this.lower_ty( - &Ty { - id: node_id, - kind: TyKind::ImplTrait(impl_trait_node_id, bounds.clone()), - span: this.lower_span(constraint.span), - tokens: None, - }, - itctx, - ); + let ty = this.ast_arena.tys.alloc(Ty { + id: node_id, + kind: TyKind::ImplTrait(impl_trait_node_id, bounds.clone()), + span: this.lower_span(constraint.span), + tokens: None, + }); + let ty = this.lower_ty(ty, itctx); hir::TypeBindingKind::Equality { term: ty.into() } }) @@ -1072,19 +1096,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } fn emit_bad_parenthesized_trait_in_assoc_ty(&self, data: &ParenthesizedArgs) { - let mut err = self.tcx.sess.struct_span_err( - data.span, - "parenthesized generic arguments cannot be used in associated type constraints", - ); // Suggest removing empty parentheses: "Trait()" -> "Trait" - if data.inputs.is_empty() { + let sub = if data.inputs.is_empty() { let parentheses_span = data.inputs_span.shrink_to_lo().to(data.inputs_span.shrink_to_hi()); - err.multipart_suggestion( - "remove these parentheses", - vec![(parentheses_span, String::new())], - Applicability::MaybeIncorrect, - ); + AssocTyParenthesesSub::Empty { parentheses_span } } // Suggest replacing parentheses with angle brackets `Trait(params...)` to `Trait<params...>` else { @@ -1098,20 +1114,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // End of last argument to end of parameters let close_param = data.inputs.last().unwrap().span.shrink_to_hi().to(data.inputs_span.shrink_to_hi()); - err.multipart_suggestion( - &format!("use angle brackets instead",), - vec![(open_param, String::from("<")), (close_param, String::from(">"))], - Applicability::MaybeIncorrect, - ); - } - err.emit(); + AssocTyParenthesesSub::NotEmpty { open_param, close_param } + }; + self.tcx.sess.emit_err(AssocTyParentheses { span: data.span, sub }); } #[instrument(level = "debug", skip(self))] fn lower_generic_arg( &mut self, arg: &ast::GenericArg, - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::GenericArg<'hir> { match arg { ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(<)), @@ -1163,7 +1175,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } _ => {} } - GenericArg::Type(self.lower_ty_direct(&ty, itctx)) + GenericArg::Type(self.lower_ty(&ty, itctx)) } ast::GenericArg::Const(ct) => GenericArg::Const(ConstArg { value: self.lower_anon_const(&ct), @@ -1173,7 +1185,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } #[instrument(level = "debug", skip(self))] - fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> &'hir hir::Ty<'hir> { + fn lower_ty(&mut self, t: &Ty, itctx: &ImplTraitContext) -> &'hir hir::Ty<'hir> { self.arena.alloc(self.lower_ty_direct(t, itctx)) } @@ -1183,11 +1195,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { qself: &Option<QSelf>, path: &Path, param_mode: ParamMode, - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::Ty<'hir> { // Check whether we should interpret this as a bare trait object. // This check mirrors the one in late resolution. We only introduce this special case in - // the rare occurence we need to lower `Fresh` anonymous lifetimes. + // the rare occurrence we need to lower `Fresh` anonymous lifetimes. // The other cases when a qpath should be opportunistically made a trait object are handled // by `ty_path`. if qself.is_none() @@ -1196,19 +1208,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { && let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = partial_res.base_res() { let (bounds, lifetime_bound) = self.with_dyn_type_scope(true, |this| { + let poly_trait_ref = this.ast_arena.ptr.alloc(PolyTraitRef { + bound_generic_params: vec![], + trait_ref: TraitRef { path: path.clone(), ref_id: t.id }, + span: t.span + }); let bound = this.lower_poly_trait_ref( - &PolyTraitRef { - bound_generic_params: vec![], - trait_ref: TraitRef { path: path.clone(), ref_id: t.id }, - span: t.span - }, + poly_trait_ref, itctx, ); let bounds = this.arena.alloc_from_iter([bound]); let lifetime_bound = this.elided_dyn_bound(t.span); (bounds, lifetime_bound) }); - let kind = hir::TyKind::TraitObject(bounds, lifetime_bound, TraitObjectSyntax::None); + let kind = hir::TyKind::TraitObject(bounds, &lifetime_bound, TraitObjectSyntax::None); return hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.next_id() }; } @@ -1225,7 +1238,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { self.ty(span, hir::TyKind::Tup(tys)) } - fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> { + fn lower_ty_direct(&mut self, t: &Ty, itctx: &ImplTraitContext) -> hir::Ty<'hir> { let kind = match t.kind { TyKind::Infer => hir::TyKind::Infer, TyKind::Err => hir::TyKind::Err, @@ -1241,7 +1254,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } else { self.next_node_id() }; - let span = self.tcx.sess.source_map().next_point(t.span.shrink_to_lo()); + let span = self.tcx.sess.source_map().start_point(t.span); Lifetime { ident: Ident::new(kw::UnderscoreLifetime, span), id } }); let lifetime = self.lower_lifetime(®ion); @@ -1253,7 +1266,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { generic_params, unsafety: self.lower_unsafety(f.unsafety), abi: self.lower_extern(f.ext), - decl: self.lower_fn_decl(&f.decl, None, FnDeclKind::Pointer, None), + decl: self.lower_fn_decl(&f.decl, None, t.span, FnDeclKind::Pointer, None), param_names: self.lower_fn_params_to_names(&f.decl), })) } @@ -1268,14 +1281,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx); } TyKind::ImplicitSelf => { + let hir_id = self.next_id(); let res = self.expect_full_res(t.id); let res = self.lower_res(res); hir::TyKind::Path(hir::QPath::Resolved( None, self.arena.alloc(hir::Path { res, - segments: arena_vec![self; hir::PathSegment::from_ident( - Ident::with_dummy_span(kw::SelfUpper) + segments: arena_vec![self; hir::PathSegment::new( + Ident::with_dummy_span(kw::SelfUpper), + hir_id, + res )], span: self.lower_span(t.span), }), @@ -1318,19 +1334,23 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { TyKind::ImplTrait(def_node_id, ref bounds) => { let span = t.span; match itctx { - ImplTraitContext::ReturnPositionOpaqueTy { origin } => { - self.lower_opaque_impl_trait(span, origin, def_node_id, bounds, itctx) - } - ImplTraitContext::TypeAliasesOpaqueTy => { - let nested_itctx = ImplTraitContext::TypeAliasesOpaqueTy; - self.lower_opaque_impl_trait( + ImplTraitContext::ReturnPositionOpaqueTy { origin, in_trait } => self + .lower_opaque_impl_trait( span, - hir::OpaqueTyOrigin::TyAlias, + *origin, def_node_id, bounds, - nested_itctx, - ) - } + *in_trait, + itctx, + ), + ImplTraitContext::TypeAliasesOpaqueTy => self.lower_opaque_impl_trait( + span, + hir::OpaqueTyOrigin::TyAlias, + def_node_id, + bounds, + false, + &ImplTraitContext::TypeAliasesOpaqueTy, + ), ImplTraitContext::Universal => { let span = t.span; let ident = Ident::from_str_and_span(&pprust::ty_to_string(t), span); @@ -1342,15 +1362,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } path } + ImplTraitContext::Disallowed( + position @ (ImplTraitPosition::TraitReturn | ImplTraitPosition::ImplReturn), + ) => { + self.tcx + .sess + .create_feature_err( + MisplacedImplTrait { + span: t.span, + position: DiagnosticArgFromDisplay(&position), + }, + sym::return_position_impl_trait_in_trait, + ) + .emit(); + hir::TyKind::Err + } ImplTraitContext::Disallowed(position) => { - let mut err = struct_span_err!( - self.tcx.sess, - t.span, - E0562, - "`impl Trait` only allowed in function and inherent method return types, not in {}", - position - ); - err.emit(); + self.tcx.sess.emit_err(MisplacedImplTrait { + span: t.span, + position: DiagnosticArgFromDisplay(&position), + }); hir::TyKind::Err } } @@ -1397,14 +1428,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { /// added explicitly in the HIR). But this includes all the lifetimes, and we only want to /// capture the lifetimes that are referenced in the bounds. Therefore, we add *extra* lifetime parameters /// for the lifetimes that get captured (`'x`, in our example above) and reference those. - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self), ret)] fn lower_opaque_impl_trait( &mut self, span: Span, origin: hir::OpaqueTyOrigin, opaque_ty_node_id: NodeId, bounds: &GenericBounds, - itctx: ImplTraitContext, + in_trait: bool, + itctx: &ImplTraitContext, ) -> hir::TyKind<'hir> { // Make sure we know that some funky desugaring has been going on here. // This is a first: there is code in other places like for loop @@ -1492,6 +1524,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }), bounds: hir_bounds, origin, + in_trait, }; debug!(?opaque_ty_item); @@ -1518,7 +1551,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { debug!(?lifetimes); // `impl Trait` now just becomes `Foo<'a, 'b, ..>`. - hir::TyKind::OpaqueDef(hir::ItemId { def_id: opaque_ty_def_id }, lifetimes) + hir::TyKind::OpaqueDef(hir::ItemId { def_id: opaque_ty_def_id }, lifetimes, in_trait) } /// Registers a new opaque type with the proper `NodeId`s and @@ -1577,7 +1610,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { LifetimeRes::Fresh { param, binder: _ } => { debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime); - if let Some(old_def_id) = self.opt_local_def_id(param) && remapping.get(&old_def_id).is_none() { + if let Some(old_def_id) = self.orig_opt_local_def_id(param) && remapping.get(&old_def_id).is_none() { let node_id = self.next_node_id(); let new_def_id = self.create_def( @@ -1626,19 +1659,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // `fn_def_id`: if `Some`, impl Trait arguments are lowered into generic parameters on the // given DefId, otherwise impl Trait is disallowed. Must be `Some` if // `make_ret_async` is also `Some`. - // `impl_trait_return_allow`: determines whether `impl Trait` can be used in return position. - // This guards against trait declarations and implementations where `impl Trait` is - // disallowed. // `make_ret_async`: if `Some`, converts `-> T` into `-> impl Future<Output = T>` in the // return type. This is used for `async fn` declarations. The `NodeId` is the ID of the - // return type `impl Trait` item. - #[tracing::instrument(level = "debug", skip(self))] + // return type `impl Trait` item, and the `Span` points to the `async` keyword. + #[instrument(level = "debug", skip(self))] fn lower_fn_decl( &mut self, decl: &FnDecl, fn_node_id: Option<NodeId>, + fn_span: Span, kind: FnDeclKind, - make_ret_async: Option<NodeId>, + make_ret_async: Option<(NodeId, Span)>, ) -> &'hir hir::FnDecl<'hir> { let c_variadic = decl.c_variadic(); @@ -1651,11 +1682,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } let inputs = self.arena.alloc_from_iter(inputs.iter().map(|param| { if fn_node_id.is_some() { - self.lower_ty_direct(¶m.ty, ImplTraitContext::Universal) + self.lower_ty_direct(¶m.ty, &ImplTraitContext::Universal) } else { self.lower_ty_direct( ¶m.ty, - ImplTraitContext::Disallowed(match kind { + &ImplTraitContext::Disallowed(match kind { FnDeclKind::Fn | FnDeclKind::Inherent => { unreachable!("fn should allow in-band lifetimes") } @@ -1669,20 +1700,63 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } })); - let output = if let Some(ret_id) = make_ret_async { - self.lower_async_fn_ret_ty( - &decl.output, - fn_node_id.expect("`make_ret_async` but no `fn_def_id`"), - ret_id, - ) + let output = if let Some((ret_id, span)) = make_ret_async { + match kind { + FnDeclKind::Trait => { + if !kind.impl_trait_in_trait_allowed(self.tcx) { + self.tcx + .sess + .create_feature_err( + TraitFnAsync { fn_span, span }, + sym::return_position_impl_trait_in_trait, + ) + .emit(); + } + self.lower_async_fn_ret_ty( + &decl.output, + fn_node_id.expect("`make_ret_async` but no `fn_def_id`"), + ret_id, + true, + ) + } + _ => { + if !kind.impl_trait_return_allowed(self.tcx) { + if kind == FnDeclKind::Impl { + self.tcx + .sess + .create_feature_err( + TraitFnAsync { fn_span, span }, + sym::return_position_impl_trait_in_trait, + ) + .emit(); + } else { + self.tcx.sess.emit_err(TraitFnAsync { fn_span, span }); + } + } + self.lower_async_fn_ret_ty( + &decl.output, + fn_node_id.expect("`make_ret_async` but no `fn_def_id`"), + ret_id, + false, + ) + } + } } else { match decl.output { FnRetTy::Ty(ref ty) => { - let context = match fn_node_id { - Some(fn_node_id) if kind.impl_trait_return_allowed() => { + let mut context = match fn_node_id { + Some(fn_node_id) if kind.impl_trait_return_allowed(self.tcx) => { + let fn_def_id = self.local_def_id(fn_node_id); + ImplTraitContext::ReturnPositionOpaqueTy { + origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), + in_trait: false, + } + } + Some(fn_node_id) if kind.impl_trait_in_trait_allowed(self.tcx) => { let fn_def_id = self.local_def_id(fn_node_id); ImplTraitContext::ReturnPositionOpaqueTy { origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), + in_trait: true, } } _ => ImplTraitContext::Disallowed(match kind { @@ -1696,7 +1770,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { FnDeclKind::Impl => ImplTraitPosition::ImplReturn, }), }; - hir::FnRetTy::Return(self.lower_ty(ty, context)) + hir::FnRetTy::Return(self.lower_ty(ty, &mut context)) } FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(self.lower_span(span)), } @@ -1707,10 +1781,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { output, c_variadic, implicit_self: decl.inputs.get(0).map_or(hir::ImplicitSelfKind::None, |arg| { - use BindingMode::{ByRef, ByValue}; let is_mutable_pat = matches!( arg.pat.kind, - PatKind::Ident(ByValue(Mutability::Mut) | ByRef(Mutability::Mut), ..) + PatKind::Ident(hir::BindingAnnotation(_, Mutability::Mut), ..) ); match arg.ty.kind { @@ -1741,12 +1814,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // `output`: unlowered output type (`T` in `-> T`) // `fn_def_id`: `DefId` of the parent function (used to create child impl trait definition) // `opaque_ty_node_id`: `NodeId` of the opaque `impl Trait` type that should be created - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn lower_async_fn_ret_ty( &mut self, output: &FnRetTy, fn_node_id: NodeId, opaque_ty_node_id: NodeId, + in_trait: bool, ) -> hir::FnRetTy<'hir> { let span = output.span(); @@ -1805,7 +1879,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { let extra_lifetime_params = self.resolver.take_extra_lifetime_params(opaque_ty_node_id); debug!(?extra_lifetime_params); for (ident, outer_node_id, outer_res) in extra_lifetime_params { - let outer_def_id = self.local_def_id(outer_node_id); + let outer_def_id = self.orig_local_def_id(outer_node_id); let inner_node_id = self.next_node_id(); // Add a definition for the in scope lifetime def. @@ -1873,8 +1947,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // // Then, we will create `fn foo(..) -> Foo<'_, '_>`, and // hence the elision takes place at the fn site. - let future_bound = - this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span); + let future_bound = this.lower_async_fn_output_type_to_future_bound( + output, + span, + ImplTraitContext::ReturnPositionOpaqueTy { + origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), + in_trait, + }, + ); let generic_params = this.arena.alloc_from_iter(collected_lifetimes.iter().map( |&(new_node_id, lifetime, _)| { @@ -1912,6 +1992,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }), bounds: arena_vec![this; future_bound], origin: hir::OpaqueTyOrigin::AsyncFn(fn_def_id), + in_trait, }; trace!("exist ty from async fn def id: {:#?}", opaque_ty_def_id); @@ -1948,8 +2029,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { let res = res.unwrap_or( self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error), ); - let l = self.new_named_lifetime_with_res(id, span, ident, res); - hir::GenericArg::Lifetime(l) + hir::GenericArg::Lifetime(self.new_named_lifetime_with_res(id, span, ident, res)) }, )); @@ -1957,8 +2037,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // Foo = impl Trait` is, internally, created as a child of the // async fn, so the *type parameters* are inherited. It's // only the lifetime parameters that we must supply. - let opaque_ty_ref = - hir::TyKind::OpaqueDef(hir::ItemId { def_id: opaque_ty_def_id }, generic_args); + let opaque_ty_ref = hir::TyKind::OpaqueDef( + hir::ItemId { def_id: opaque_ty_def_id }, + generic_args, + in_trait, + ); let opaque_ty = self.ty(opaque_ty_span, opaque_ty_ref); hir::FnRetTy::Return(self.arena.alloc(opaque_ty)) } @@ -1967,8 +2050,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_async_fn_output_type_to_future_bound( &mut self, output: &FnRetTy, - fn_def_id: LocalDefId, span: Span, + mut nested_impl_trait_context: ImplTraitContext, ) -> hir::GenericBound<'hir> { // Compute the `T` in `Future<Output = T>` from the return type. let output_ty = match output { @@ -1976,10 +2059,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // Not `OpaqueTyOrigin::AsyncFn`: that's only used for the // `impl Future` opaque type that `async fn` implicitly // generates. - let context = ImplTraitContext::ReturnPositionOpaqueTy { - origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), - }; - self.lower_ty(ty, context) + self.lower_ty(ty, &mut nested_impl_trait_context) } FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])), }; @@ -2005,7 +2085,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_param_bound( &mut self, tpb: &GenericBound, - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::GenericBound<'hir> { match tpb { GenericBound::Trait(p, modifier) => hir::GenericBound::Trait( @@ -2018,24 +2098,24 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } } - fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime { + fn lower_lifetime(&mut self, l: &Lifetime) -> &'hir hir::Lifetime { let span = self.lower_span(l.ident.span); let ident = self.lower_ident(l.ident); self.new_named_lifetime(l.id, l.id, span, ident) } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn new_named_lifetime_with_res( &mut self, id: NodeId, span: Span, ident: Ident, res: LifetimeRes, - ) -> hir::Lifetime { + ) -> &'hir hir::Lifetime { let name = match res { LifetimeRes::Param { param, .. } => { let p_name = ParamName::Plain(ident); - let param = self.resolver.get_remapped_def_id(param); + let param = self.get_remapped_def_id(param); hir::LifetimeName::Param(param, p_name) } @@ -2052,17 +2132,21 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }; debug!(?name); - hir::Lifetime { hir_id: self.lower_node_id(id), span: self.lower_span(span), name } + self.arena.alloc(hir::Lifetime { + hir_id: self.lower_node_id(id), + span: self.lower_span(span), + name, + }) } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn new_named_lifetime( &mut self, id: NodeId, new_id: NodeId, span: Span, ident: Ident, - ) -> hir::Lifetime { + ) -> &'hir hir::Lifetime { let res = self.resolver.get_lifetime_res(id).unwrap_or(LifetimeRes::Error); self.new_named_lifetime_with_res(new_id, span, ident, res) } @@ -2117,7 +2201,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { GenericParamKind::Type { ref default, .. } => { let kind = hir::GenericParamKind::Type { default: default.as_ref().map(|x| { - self.lower_ty(x, ImplTraitContext::Disallowed(ImplTraitPosition::Type)) + self.lower_ty(x, &ImplTraitContext::Disallowed(ImplTraitPosition::Type)) }), synthetic: false, }; @@ -2125,7 +2209,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { (hir::ParamName::Plain(self.lower_ident(param.ident)), kind) } GenericParamKind::Const { ref ty, kw_span: _, ref default } => { - let ty = self.lower_ty(&ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)); + let ty = self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type)); let default = default.as_ref().map(|def| self.lower_anon_const(def)); ( hir::ParamName::Plain(self.lower_ident(param.ident)), @@ -2135,7 +2219,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } } - fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext) -> hir::TraitRef<'hir> { + fn lower_trait_ref(&mut self, p: &TraitRef, itctx: &ImplTraitContext) -> hir::TraitRef<'hir> { let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) { hir::QPath::Resolved(None, path) => path, qpath => panic!("lower_trait_ref: unexpected QPath `{:?}`", qpath), @@ -2143,11 +2227,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { hir::TraitRef { path, hir_ref_id: self.lower_node_id(p.ref_id) } } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn lower_poly_trait_ref( &mut self, p: &PolyTraitRef, - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::PolyTraitRef<'hir> { let bound_generic_params = self.lower_lifetime_binder(p.trait_ref.ref_id, &p.bound_generic_params); @@ -2155,14 +2239,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { hir::PolyTraitRef { bound_generic_params, trait_ref, span: self.lower_span(p.span) } } - fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy<'hir> { + fn lower_mt(&mut self, mt: &MutTy, itctx: &ImplTraitContext) -> hir::MutTy<'hir> { hir::MutTy { ty: self.lower_ty(&mt.ty, itctx), mutbl: mt.mutbl } } + #[instrument(level = "debug", skip(self), ret)] fn lower_param_bounds( &mut self, bounds: &[GenericBound], - itctx: ImplTraitContext, + itctx: &ImplTraitContext, ) -> hir::GenericBounds<'hir> { self.arena.alloc_from_iter(self.lower_param_bounds_mut(bounds, itctx)) } @@ -2170,11 +2255,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_param_bounds_mut<'s>( &'s mut self, bounds: &'s [GenericBound], - itctx: ImplTraitContext, + itctx: &'s ImplTraitContext, ) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> { bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx)) } + #[instrument(level = "debug", skip(self), ret)] fn lower_generic_and_bounds( &mut self, node_id: NodeId, @@ -2200,16 +2286,19 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { node_id, &GenericParamKind::Type { default: None }, bounds, - ImplTraitContext::Universal, + &ImplTraitContext::Universal, hir::PredicateOrigin::ImplTrait, ); + let hir_id = self.next_id(); + let res = Res::Def(DefKind::TyParam, def_id.to_def_id()); let ty = hir::TyKind::Path(hir::QPath::Resolved( None, self.arena.alloc(hir::Path { span: self.lower_span(span), - res: Res::Def(DefKind::TyParam, def_id.to_def_id()), - segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident))], + res, + segments: + arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)], }), )); @@ -2235,7 +2324,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { c.value.span, "using `_` for array lengths is unstable", ) - .emit(); + .stash(c.value.span, StashKey::UnderscoreForArrayLengths); hir::ArrayLen::Body(self.lower_anon_const(c)) } } @@ -2372,11 +2461,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } fn pat_ident(&mut self, span: Span, ident: Ident) -> (&'hir hir::Pat<'hir>, hir::HirId) { - self.pat_ident_binding_mode(span, ident, hir::BindingAnnotation::Unannotated) + self.pat_ident_binding_mode(span, ident, hir::BindingAnnotation::NONE) } fn pat_ident_mut(&mut self, span: Span, ident: Ident) -> (hir::Pat<'hir>, hir::HirId) { - self.pat_ident_binding_mode_mut(span, ident, hir::BindingAnnotation::Unannotated) + self.pat_ident_binding_mode_mut(span, ident, hir::BindingAnnotation::NONE) } fn pat_ident_binding_mode( @@ -2465,14 +2554,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { /// bound, like the bound in `Box<dyn Debug>`. This method is not invoked /// when the bound is written, even if it is written with `'_` like in /// `Box<dyn Debug + '_>`. In those cases, `lower_lifetime` is invoked. - fn elided_dyn_bound(&mut self, span: Span) -> hir::Lifetime { + fn elided_dyn_bound(&mut self, span: Span) -> &'hir hir::Lifetime { let r = hir::Lifetime { hir_id: self.next_id(), span: self.lower_span(span), name: hir::LifetimeName::ImplicitObjectLifetimeDefault, }; debug!("elided_dyn_bound: r={:?}", r); - r + self.arena.alloc(r) } } |